Replacing the brushes frequently

Heating the machine by running periodically

Cleaning the commutator segments regularly

Blowing hot air in to the machine during maintenance

Shunt generator

Series generator

Compound generator

Separately excited generator

Shunt generator

Series generator

Differential compound generator

Cumulative compound generator

Low current low voltage

High current low voltage

Low current high voltage

High current high voltage

To reduce the copper loss

To increase the residual magnetism

To decrease the residual magnetism

To reduce the reluctance of magnetic path